CA1244192A

CA1244192A - Method for making a dicyclopentadiene thermoset polymer

Info

Publication number: CA1244192A
Application number: CA000418637A
Authority: CA
Inventors: Daniel W. Klosiewicz
Original assignee: Hercules LLC
Current assignee: Hercules LLC
Priority date: 1982-01-25
Filing date: 1982-12-24
Publication date: 1988-11-01
Also published as: US4400340A; JPH0328451B2; JPS58129013A

Abstract

METHOD FOR MAKING A DICYCLOPENTADIENE THERMOSET POLYMER

Abstract of the Disclosure A method of making a thermoset polydicyclopentadiene by first combining a plurality of reactant streams, one contain-ing the activator of a metathesis-catalyst system, a second containing the catalyst of a metathesis-catalyst system and at least one containing dicyclopentadiene; then immediately injecting this combination into a mold where polymerization results in the formation of a tough, rigid thermoset polymer with high modulus and excellent impact strength.

Description

~ his invention relates to a method for the preparation of a polymer of dicyclopentadiene (hereinafter referred to as DCPD). In particular, it relates to employing a meta-thesis-catalyst system to form a high modulus, high impact strength thermoset poly(DCPD) homopolymer. In a preferred embodiment the homopolymer is formed when two solutions, one a catalyst/
monomer mixture and the other an activator/monomer mixture, are combined in a reaction injection molding (hereinafter referred to as RIM) machine and then injected into a mold.
Any good thermoset polymer should meet at least two criteria. It should have desirable physical properties and it should lend itselE to easy synthesis and forming. Among the most desirable physical properties for many polymers is a combination of high impact strength and high modulus. ~
standar5dt~est for impact strength is the notched Izod impact ¦ ~ test, ~ No. D-25~. For an unreinforced thermoset polymer to have good impact strength, its notched Izod impact should be at least 1.5 ft~ lb/in. notch. It is desirable that this good impact strength be combined with a modulus of at least about 150,000 psi at ambient temperature. Thermoset polymers with high impact strength and high modulus find useful appli-cations as engineering plastics in such articles of manufac-ture as automobiles, appliances and sports equipment. ~mong the critical factors in the synthesis and forming of a thermo-set polymer are the conditions required to make the polymerset up or gel. Many thermoset polymers require considerable time, elevated temperature and pressure, or additional steps after the reactants are mixed before the setting is complete.
~hile some references to poly(DCP~) have been made in the literature, a thermoset homopolymer having high impact strength and high modulus has never been described. Charas-teristics of thermoset polymers include insolubility in common solvents such as gasoline, naphtha, chlorinated hydrocarbons, and aromatics as well as resistance to flow a-t elevated tem-peratures.
Wor~ has been done on the metathesis copolymerization ofDCPD with one or more other monomers to produce soluble copolymers. This copolymer formation has resulted in the pro-duction of unwanted insoluble by-products. U.S. Patent ~,002,815, for instance, teaches the copolymerization of cyclopentene with DCPD, describes an insoluble by-product and suggests that the by-product could be a gel of a DCPD homo-polymer.
Some work, usually in an attempt to produce soluble poly-(DCPD's), has been done on the metathesis homopolymerizationof DCPD. Japanese unexamined published patent applications KOKAI 53-92000 and 53-111399 disclose soluble poly(DCPD's).
Several syntheses of soluble poly(DCPD) have produced insol-uble by-products. Takata et al, J. Chem. Soc. Japan Ind.
Chem. Sect., 69, 711 (1966), discloses the production of an insoluble poly(DCPD) by-product from the ~iegler-Natta cata-lyzed polymerization of DCPD; Oshika et al, Bulletin of the Chemical Society of Japan, discloses the production of an insoluble polymer when DCPD is polymerized with ~C16, AlEt3/
TiC14 or AlEt3MoC15; and Dall Asta et al, Die Ma~romolecular Chemie 130, 153 (1969), discloses an insoluble by-product pro-duced when a ~C16/AlEt2Cl catalyst system is used to form poly(DCPD).
In U.S. Patent 3,627,739 ('739), a thermoset poly(DCPD) is the object of synthesis. The poly(DCPD) of '739 is brit-tle, having an Izod impact strength of only 0.78.
Not only is it desirable that the thermoset polymer have high impact strength, but it is also desirable -that it be eas-ily synthesized and formed. A P~IM process achieves this sec-ond goal by in-mold polymerization. ~he process involves the mixing of two or more low viscosity reactive streams. ~he combined streams are then injected into a mold where they quickly set up into a solid infusible mass. ~IM is especially suited for molding large intricate objects rapidly and in low cost equipment. Because the process requires only low pres-sures, the molds are inexpensive and easily changed. Further-more, since the initial materials have low viscosity, massive extruders and molds are not necessary and energy requirements are minimal compared to the injection molding or compression molding commonly used. For a RIM system to be of use with a particular polymer, certain requirements must be met: 1) the individual streams must be stable and must have a reasonable shelf-life under ambient conditions; 2) it must be possible to mix the streams thoroughly without their setting up in the mixing head; 3) when injected into the mold, the materials must set up to a solid system rapidly; and 4) any additives-fillers, stabilizers, pigments, etc. - must be added before the material sets up. Therefore, the additives selected must not interfere with the polymerization reaction.
It can be seen that when developing a RIM process a tradeoff must be made. It is desirabla that the polymer set up quickly, but the polymerization cannot be too quick. ~he components cannot be so reactive that they set up in the mix-ing head before they can be injected into the mold. Once in the mold, however, the polymer should set up as quickly as possible. It is not desirable that the polymer take a long time or require additlonal steps to gel completely.
It is known in the prior art to base a RIM system on the combination of two reactive monomers, e.g., the polyol and the diisocyanate monomers employed in a polyurethane system. It is known, but not in the context of a RIM system, to combine two or more reactive parts of a catalyst, where one or both are in solution with the monomer, to form a homopolymer. Aprocess which employs two separate streams based on a two part catalyst system to produce a thermoset polymer in such a man-ner that the streams can be combined in one place and -then rapidly set up in another is unique and is a substantial con-tribution to the art.
U.S. Patent 2,~46,~26, Larson, claims the combination o~two vapor streams, one containing a vaporizable alkylaluminum compound and the other containing a vaporizable compound of $ L~

Group IV-s, V-B, or VI-B metal, where at least one of the streams contains a gaseous monomer. The vapor streams are combined and a thermoplastic polymer is formed in the same reaction zone. United States Patent 3,492,245, Calderon et al, discloses the in-situ formation of a catalyst system containing an organoaluminum compound, a tungsten hexahalide and a hydroxy compound. Again, the reactive components are mixed and the polymerization of an unsaturated alicyclic compound occurs in the same vessel. United States Patent 3,931,357, Meyer, teaches a process for forming a soluble graft copolymer of a polydiene or a polyalkenamer and an unsaturated polyolefin rubber which entails combining a stream containing a metathesis-catalyst component from a metal of subgroups V through VII of the periodic table with a stream containing an alkyl or a hydride of a metal from main groups I
through VII of the periodic table prior to the metathesis reaction proper. Since the copolymer is soluble, there is no requirement that it rapidly set up.
This invention encompasses a method for producing a high impact strength, high modulus thermoset homopolymer comprising polymerized units of DCPD by using a two part metathesis-catalyst system. The DCPD polymer formed is a tough, rigid material with high modulus and excellent impact strength. The flexural modulus is in the range of about 150,000 to about 300,000 psi. and the notched Izod impact strength is at least 1.5 ft. lb./
in. notch.
The invention provides a method of making a thermoset homopolymer comprising: firY~7 combining a plurality of reactant ,~ ~. ., streams, one of which contains the activator of a metathesis-catalyst system, and a second which contains the catalyst of said metathesis-catalyst system, and at least one of which contains dicyclopentadiene to form a reaction mixture and then, immediately injecting the reaction mixture into a mold where polymerization occurs.
The invention als3 provides a thermoset dicyclopentadiene polymer having a flexural modulus in the range of 150,000 to about 300,000 psi and a notched Izod impact strength of at least 1.5 ft.
1b./in. notch and which also contains an elastomer.
The polymer can be synthesized by reacting DCPD with a two part metathesis-catalyst system. The first part of the cat alyst system is comprised of a metathesis catalyst, preferably WOCl4, WCl6 or a combination of WCl6 plus an alcohol or phenol.
The second part of the catalyst system is comprised of an activator such as SnBu4, AlEt3, AlEt2Cl, AlEtCl2, or similar compounds. In a preferred synthesis, the activator is AlEt2Cl. The catalyst may be mixed with the dicyclopentadiene before the catalyst is mixed with the activator. Also in the preferred synthesis the activator containing solution includes an ester, ether, ketone or nitrile which serves to moderate the rate of polymerization. Examples of suitable moderators are ethyl benzoate and di~n-butyl ether.
In a preferred embodiment the two metathesis-catalyst system components, plus the monomer, form the basis for at least two sep-arate streams which can be mixed in the head of a RIM machine and then injected into a mold where they will quickly set up into a tough, infusible mass. Various additives such as fillers and stabilizers can be added to modify '~

the properties of the thermoset polymer.
Dicyclopentadiene can be polymerized in such a manner that the resulting product is a thermoset homopolymer having high impact strength and high modulus. The preferred monomer is commercially available endo~DCPD (3a,4,7,7a-tetrahydro-4,7-methano-lH-indene). The exo-isomerj while not commercially available, can be used just as well. The preferred commercially available material normally has a purity of 96-97~. Commercially available material should be purified in order to prevent impurities from inhibiting the polymeriza-tion. The low boiling fraction should be removed. This can be done by stripping away several percent of the unsaturated four to six carbon atom volatiles, i.e., the volatiles distilled below 100C at about 90 + 3 torr. It is often desirable to purify the starting material even fur-ther by treatment with silica gel. Additionally, the water content of the starting material should be below about 100 ppm. The presence of water interferes with polymerization by hydrolysis of both the catalyst and the activator components of the catalyst system. For example r water can be removed by azeotropic distillation under reduced pressure. Even after these steps the monomer still contains some impurities. It should be understood, therefore, that throughout this description the term homopolymer refers to the polymer resulting from essentially pure starting material.
The homopolymerization of the purified DCPD is catalyzed by a two part metathesis-catalyst system. In the preferred system, one part contains a tungsten containing catalyst, such as a , .
- 5a -gf~

tungsten halide or tungsten oxyhalide, preferably WC16 or WOC14.
The other part contains an activator which is an alkylaluminum compound. The alkylaluminum compound can be an alkylaluminum dihalide or dialkylaluminum halide where the alkyl group contains one to ten carbon atoms. In the preferred activator the - 5b -alkyl group is ethyl with diethyl aluminum chloride being most preferred.
One part of the catalyst system comprises the tungsten containing catalyst, as described above, preferably in solu-tion with DCP~ monomer. The tungsten compound if unmodified,will rapidly polymerize the monomer. Consequently, the tung-sten compound should first be suspended in a small amount of a suitable solvent. The solvent must not be susceptible to halogenation by the tungsten compound. ~xamples of preferred solvents are benzene, toluene, chlorobenzene, dichlorobenzene, and trichlorobenzene. Sufficient solvent should be added so that the tungsten compound concentration is between about 0.1 and 0.7 mole per liter of solvent.
The tungsten compound can be solublized by the addition of a small amount of an alcoholic or a phenolic compound.
Phenolic compounds are preferred. Suitable phenolic compounds include phenol, alkyl-phenols, and halogenated phenols, with tert-butyl phenol, tert-octyl phenol and nonyl phenol being most preferred. The preferred molar ratio of tungsten com-pound/phenolic compound is from about 1:1 to about 1:3. Thetungsten compound/phenolic compound solution can be made by adding the phenolic compound to a tungsten compound/organic solvent slurry, stirring the solution and then blowing a stream of a dry inert gas through the solution to remove the hydrogen chloride which is formed. Alternatively, a phenolic salt, such as a lithium or sodium phenoxide, can be added to a tungsten compound/organic solvent slurry, the mixture stirred until essentially all the tungsten compound is dissolved, and the precipitated inorganic salt removed by filtration or cen-trifugation. All of these steps should be carried out in theabsence of moisture and air to prevent deactivation of the catalyst.
To prevent premature polymerization of the tungsten com-pound/monomer solution, which would occur within a matter of hours, from about 1 to about 5 moles of a Lewis base or a chelating agent can be added per mole of tungsten compound.
Preferred chelants include acetylacetones, alkyl acetoace-tates, where the alkyl group contains from one to ten carbon 9~2 atoms; preferred Lewis bases are nltriles and ethers such as benzonitrile and tetrahydrofuran. The improvement in the stability and shelf-life of the tungsten compound/monomer solution is obtained whether the complexing agent is added before or after the phenolic compound. When purified DCPD is added to this catalyst solution it forms a solution which is stable and has a shelf-life of several months.
In another aspect the invention provides a catalyst part of a metathesis-catalyst system comprising a catalyst and a Lewis base or a chelant wherein the molar ratio of catalyst to Lewis base or chelant is about 1:5.
The other part of the metathesis-catalyst system comprises the activator, as described above, preferably in DCPD
monomer. This mixture is storage stable and therefore, unlike the tungsten compound/monomer solution, needs no additives to prolong its shelf-life. If, however, an unmodified activator/
monomer solution is mixed with the catalyst/monomer solution, the polymerization would initiate instantaneously and the polymer cou]d set up in the mixing head. The onset of polymerization can be delayed by adding a moderator to the activator/monomer solution.
Ethers, esters, ketones and nitriles can act as moderators for the alkylaluminum compounds. Isopropyl ether, di-n-butyl ether, ethyl benzoate, phenylethyl acetate and diisopropyl ketone are preEerred.
Ethyl benzoate and di-n-butyl ether are most preferred. The preferred ratio of the alkylaluminum to moderator is from about 1:1.5 to about 1:5 on a molar basis.
In yet another aspect the invention provides an activator part of a metathesis-catalyst system in dicyclopenta-diene and a moderator, wherein the activator is Sn~u4 or an alkylaluminum compound and the ratio of alkylaluminum to moderator is from about 1:1.5 to about 1:5 on a molar basis.
The polymerization time required for gelation is also temperature dependent. As the temperature at which the reaction is carried out is increased the reaction rate will also increase.
For every eight degree increase in temperature the reaction rate will approximately double. Consequently, to keep the reaction rate controlled at higher reaction temperatures a less active formulation of the metathesis-catalyst system should be used.
~ hat is ultimately required is that when the catalyst system's components are combined, the resulting DCPD to catalyst ratio will be from about ],000:1 to about 15,000:1 on a molar basis, preferably 2,000:1 and the DCPD to activator ratio will be from about 100:1 to about 2000:1 on a molar basis, preferably about 200:1 to about 500:1. To illustrate a preferred combination:
sufficient DCPD is added 7a -- 8 - ~

to a O.l M tungsten containing catalyst solution prepared as described above, so that the final tungsten compound concen-tration is 0.007 molar. ~his corresponds to a DCPD to tung~
sten compound ratio of lOOO:l. Sufficient DCPD is added to the Et2AlCl solution, prepared as described above, so that the alkylaluminum concentration is 0.048 M. This corresponds to a DCPD to alkylaluminum ratio of 150:l. If these two streams are mixed in a l:l ratio, the final ratio of DCPD to tungsten compound will be 2000:1, the final ratio of DCPD to al]sylalu-minum will be 300:1 and the final ratio of tungsten compoundto alkylaluminum will be about l:7. The illustrated combina-tion is not the lowest catalyst level at which moldings can be made, but it is a practical level that provides for excess catalyst if impurities in the system consume some of the cata-lyst components~ A higher alkylaluminum level will not onlyincrease costs and residual chlorine levels but may result in a less satisfactory cure~ Too low a tungsten compound concen-tration results in incomplete conversion. A wide range of alkylaluminum activator to tungsten catalyst formulations pro-duce samples which have good out-of-mold properties such as tear resistance, stiffness, residual odor, and surface proper-ties.
In a preferred synthesis, the poly(DCPD) is made and molded with the RIM process. ~he two parts of the metathesis-catalyst system are each mixed with DCPD, to form stable solu-tions which are placed in separate vessels. ~hese containers provide the source for separate streams. mhe two streams are combined in the RIM machine's mixing head and then injected into a warm mold where they quickly polymerize into a solid, infusible mass. he invention is not intended to be limited to systems employing two streams each containing monomer. It will be obvious to one skilled in the art that there may be situations where it is desirable to have monomer incorporated in just one stream or to employ more than two streams where the additional streams contain monomer and/or additives.
~ hese streams are completely compatible with conventional RI~I equipment. Metathesis-catalyzed polymerizations are known to be inhibited by oxygen so it is necessary to store the com-ponents under an inert gas but, surprisingly, it is not neces-sary to blanket the mold with an inert gas. The streams are combined in the mixing head of a RIM machine. Turbulent mix-5 ing is easy to achieve because the process involves low molec-ular weigh-t, rapidly diffusing components. Typically the mix-ing heads have orifices about 0.03 inch in diameter and a jet velocity of about 400 ft/sec. After being combined the mix-ture is injected into a mold maintained at 35-100C, prefer-10 ably 50-70C. The mold pressure is in the range of about 10-50 psi. A rapid exothermic reaction occurs as the poly(DCPD) sets up. The mold can be opened in as little as 20-30 seconds after the combined streams have been injected. In this short time heat removal is not complete and the polymer is hot and 15 flexible. The polymer can be removed from the mold immedi-ately while hot or after cooling. After the polymer has cooled it will become a rigid solid. ''he total cycle time may be as low as 0.5 minute. Post-curing is desirable but not essential, to bring the samples to their final stable dimen-20 sional states, to minimize residual odors, and to improvefinal physical properties. Post-curing at about 175C for about 15 minutes is usually sufficient.
The product has a flexural modulus of about 150,000 to 300,000 psi and a notched Izod impact resistance of at least 25 about 1.5 ft. lb/in. notch. The homopolymer is insoluble in common solvents such as gasoline, naphthas, chlorinated hydro-carbons and aromatics, resistant to flow at temperatures as high as 350C and readily releases from the mold.
Various additives can be included to modify the proper-30 ties of poly(DCPD). Possible additives include fillers, pig-ments, antioxidants, light stabilizers and polymeric modi-fiers. Because of the rapid polymerization time the additives must be incorporated before the DCPD sets up in the mold. It is often desirable that the additives be combined with one or 35 both of the catalyst system's streams before being iniected into the mold. Fillers can also be charged to the mold cav-ity, prior to charging the reaction streams, if the fillers are such that the reaction stream can readily flow around them to fill and the remaining void space in the mole. It is essential that the additlves not affect catalytic activity.
One class of possible additives is reinforcing agents or fillers. ~hese are compounds which can increase the polymer's flexural modulus with only a small sacrifice in impact resis-tance. Possi~le fillers include glass, wollastonite, mica, carbon black, talc, and calcium carbonate. It is surprising that in spite oE the highly polar nature of their surfaces these fillers can be added without appreciably affecting the polymerization rate. From about 5% to 75% by weight may be incorporated. This and all subsequent percentages are based on the weight of the -Einal product. he addition of fillers which have modified surface properties are particularly advan-tageous. The exact amount of a particular filler to be usedin a particular situation will be easily determinable and will depend on the preferences of the practitioner. The addition of fillers also serves to decrease the mold shrinkage of the product. AEter a short post cure at 150-200C an unfilled product will shrink from about 3.0 to about 3.5% whereas add-ing 20-25 wt~ filler will decrease the shrin]sage to 1.5-2% and adding 33 wt% filler will further decrease shrinkage to about 1~ .
Since poly(DCPD) contains some unsaturation it may be sub]ect to oxidation. ~he product can be protected by the incorporation of as much as about 0 wt% of a phenolic or amine antioxidant. Preferred antioxidants include 2,~-tert-butyl-p-cresol, N,~'-diphenyl-p-phenylene diamine and tetrakis [methylene(3,5-di-t-butyl-~-hydroxy cinnamate)] methane.
l~hile the antioxidant can be added to either or both streams, incorporation into the activator/monomer stream is preferred.
mhe addition of a elastomer can increase the polymer's impact strength 5-10 fold with only a slight decrease in Elex-ural modulus. ~he e]astomer can be dissolved in either or both of the DCPD streams in the 5-10 wt% range without caus-ing an excessive increase in the solution viscosity. Useful elastomers include natural rubber, butyl rubber, polyisoprene, polybutadiene, polyisobutylene, ethylene-propylene copolymer, styrene-butadiene-styrene triblock rubber, styrene-isoprene-styrene triblock rubber and ethylene-propylene diene terpoly-mers. mhe amount of elastomer used is determined by its molecular weight and is limited by the viscosity of the streams. mhe streams cannot be so viscous tha-t adequate mix-ing is not possible. The Brookfield viscosity of DCPD is about 6 cps at 35~C. Increasing the viscosity to between about 300 cps and about 1000 cps alters the mold filling char-acteristics of the combined streams. An increase in viscosityreduces leakage from the mold and simplifies the use of fil-lers by decreasing the settling rates of the solids. An exam-ple of a preferred elastomer is styrene-butadiene styrene tri-block. ~here 10 wt% of this additive is incorporated into the streams not only is the viscosity increased to about 300 cps but the impact strength of the final product also increases.
Although the elastomer can be dissolved in either one or both of the streams it is desirable that it be dissolved in both.
When the two streams have similar viscosities more uniform mixing is ob-tained.
Examples 1 and 2 -In Example 1 a 0.1 M solution of a tungsten containing catalyst solution was prepared by adding 20 grams of WC16 in 460 ml of dry toluene under a N2 atmosphere and then adding a solution of 8.2 grams of p-tert-butyl phenol in 30 ml of tol-uene. mhe catalyst solution was sparged overnight with nitro-gen to remove the HCl generated by the reaction oE ~Cl~ with the p-tert-butylphenol. In this and in all the following examples phenol is used as a shorthand for p-tert-butylphenol and for simplicity the solution is referred to as ~lJC16/phenol.
Then a 0.033 M catalyst/monomer solution was prepared by mix-ing under nitrogen 10 ml of DCPD, 0.07 ml of benzonitrile and 5 ml of the 0.1 M catalyst solution. An activator/monomer solution was prepared by combining, under nitrogen, 8.6 ml of DCPD, 0.1 ml of isopropyl ether and 0.36 ml of 1.0 M Et2~91Cl in DCPD.
Polymerization was accomplished by adding 1.1 ml of the 0.033 M catalyst/monomer solution to 8.9 ml of the activator/

monomer solution. Both solutions were intially at 25C. They were vigorously mixed. After a brief induction period and a sharp exotherm was observed. A solid, insoluble polymer was formed. The time that elapsed until rapid ~olymerization began and the total exotherm of the sample above the starting temperature are shown in Table I.
In Example 2 the above procedure was repeated except that 0.36 ml of 1.0 M EtAlC12 was used in place of Et2AlCl to pre-pare the activator solution and the reaction was started at aooC~
A solid, insoluble polymer was formed. The results are shown in Tabls I.
-Table I

Example 1 Example 2 DCPD 72 mmol 72 mmol 15 WC16/Phenol 0.036 mmol 0.036 mmol Et2AlC1 0.36 mmol EtAlC12 _ 0.36 mmol Benzonitrile 0.04 mmol 0.04 mmol Isopropyl ether 0.72 mmol 0.72 mmol 20 Initial memperature 25C ~0C
Time until exotherm 15 sec. 4~5 sec.
Exotherm 122C 147C

Examples 3-8 In Examples 3 through 8 the procedure described in Exam-ple 1 was repeated except that different moderators were added to the activator/monomer solution. In each example the ratio of moles moderator to moles of Et2AlCl was held constant at

2:1. In example 3, di-n-butyl ether was added while in Exam-ple ~, diisopropyl ether was used. In Example 5, ethyl benzo-ate was used while in Example 5, phenylethyl ace-tate was added. In Example 7, diisopropyl ketone was added. L,astly, in Example 8, tetrahydrofuran was added. In each example the initial temperature was 25C (+1C). Example 8 was the only case where a solid insoluble polymer was not obtained. The results are listed in Table II.

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Examples 9-12 In Examples 9 through 12 the activator to catalyst ratios were varied. In Example 9, 0.88 ml of catalyst/monomer solu-tion, described in Example 1 was added to 7.1 ml of DCPD con-taining sufficient Et2AlCl and di-n-butyl ether to give the composition listed in Table III. In Example 10, 0.44 ml of the same catalyst/monomer solution as used in Exa~ple 9 was added to 7.5 ml of the same activator/monomer solution used in Example 9, to give the final composition listed in Table III.
In Example 11, 4.0 ml of a catalyst/monomer solution prepared by mixing 20 ml of DCPD with l.S ml of a 0.1 M WC16/phenol solution, was mixed with 4.0 ml of an activator/monomer solu-tion. In this activator solution there was sufficient Et2AlCl to give a DCPD to alkylaluminum ratio of 100:1 and sufficient di-n-butyl ether to give a di-n-butyl ether to alu-minum ratio of 2:1. In Example 12, 4.0 ml of the catalyst/
monomer solution used in ~xample 11 was mixed with 2.0 ml of DCPD and 2.0 ml of the activator/monomer solution used in Example 11. In each case a solid, insoluble polymer was formed. The results of these reactions showing a variation in the exotherms due to variations in the Al/~l ratio, are listed in Table III.

Table III

Example 9 Example 10 Example 11 Example 12 25 DCPD 57.6 mmol 57.6 mmol 57.6 mmol 57.6 mmol WC16/Phenol 0.023 mmol 0.0145 mmol 0.029 mmol 0.029 mmol Et2AlC1 0.29 mmol 0.29 mmol 0.29 mmol 0.145 mmol Di -n-butyl ether 0.58 mmol 0.58 mmol 0.58 mmol 0.29 mmol 30 Benzonitrile 0.033 mmol 0.016 mmol 0.033 mmol 0.033 mmol DCPD/Al 200 200 200 400 Al/W 10/1 20/1 10/1 5/1 Time to Exotherm 50 sec. 48 sec. 33 sec. 43 sec.
Exotherm 153C 120C 145C 168C

Examples 13-15 In Examples 14-15 a small amount of a polar material was added to the catalyst/monomer solution in order to illustrate the effect of polar materlal on shelf-life. In ~xample 13, a catalyst/monomer solution was prepared by adding 2.0 ml of a 0.1 M tungsten containing catalyst solution, as described in Example 1, to 20 ml of DCPD in a nitrogen purged tube. This mixture gelled to a non-flowing material within 24 hours. In Example 14, the same procedure was carried out except that 0.03 ml of benzonitrile was added, giving a final benzonitrile to tungsten halide ratio of 1.5:1. This mixture did not gel and was catalytically active after 4 weeks. Example 15 illus-trates the result when tetrahydrofuran was added to give a tetrahydrofuran to tungsten halide ratio of 1.5:1. Again, a greatly improved storage stability was observed. The results are listed in Table IV.

Table IV

Example 13 Example 14 Example 15 DCPD 130 mmol 130 mmol 130 mmol 20 ~YC16/Phenol 0.2 mmol 0.2 mmol 0.2 mmol Ben~onitrile - 0.3 mmol Tetrahydrofuran - - 0.3 mmol Condition after 24 hours gelled low viscosity low viscosity 25 Condition after 4 weeks gelled low viscosity low viscosity Activity after 4 weeks gelled acceptable acceptable Examples 16-18 In Examples 16-18, the concentration of di-n-butyl ether incorporated into the activator/monomer solution to serve as a moderator was varied. In Example 16, the procedure used in Example 1, was followed with the exception that 0.078 ml of n-butyl ether was substituted for the diisopropyl ether. This gave a final ratio of di-n-butyl ether to alkylaluminum of 1.5:1. In Example 17, the procedure was repeated except that - 16 ~

0.156 ml of di-n-butyl ether was added, giving a final ether/
Al ratio of 3:1. In Example 18, sufficient di-n-butyl ether was added to bring the final ether to alkylaluminum ratio to 5:1. All the reactions in Table V were initiated at 25C. In each case a solid, insoluble polymer was formed. The results of the reactions are listed in Table V.

Table V

Example 16 Example 17 Example 18 DCPD 57.6 mmol 57.6 mmol 57.6 mmol 10 WC16/Phenol 0.029 mmol 0.029 mmol 0.029 mmol Et2AlC1 0.29 mmol 0.29 mmol 0.29 mmol Di-n-butyl ether 0.43 mmol 0.86 mmol 1.45 mmol Benzonitrile 0.033 mmol 0.033 mmol 0.033 mmol Ether/Al 1.5 3.0 5.0 Elapsed time until exotherm 36 sec. 55 sec. 75 sec.
Exotherm 150C 158C 159C

Examples 19-21 In Examples 19-21, the level of Et2AlCl used in the poly-merization of DCPD was varied. In Example 19, 18.5 ml of DCPD
was mixed under N2 with 1.5 ml of a 1.0 M solution of Et2AlCl in DCPD and with 0.55 ml of di-n-butyl ether. Then in a N2 purged tube 8.9 ml of this activator/monomer solution was mixed with 1.1 ml of a catalyst/monomer solution as described in Example 1. In Example 20, 4.5 ml of the activator/monomer solution used in Example 19 was combined with 4.4 ml of DCPD
and 1.1 ml of the catalyst/monomer solution used in Example 20. In Example 21, 2.5 ml of the activator/monomer solution used in Example 19 was combined under N2 with 6.4 ml of DCPD
and 1.1 ml of the catalyst/monomer solution used in Example 19. mhe final compocitions of these reaction mixtures are listed in Table VI. All reactions were initiated at 25C.

Table VI

Example 19 Example 20 Example 21 DCPD 72 mmol 72 mmol 72 mmol ~Cl6/Phenol 0.036 mmol 0.036 mmol 0.036 mmol ~t2AlC1 0.72 mmol 0.36 mmol 0.20 mmol Di-n-butyl ether 1O44 mmol 0.72 mmol 0.40 mmol Benzonitrile 0.04 mmol 0.04 mmol 0.04 mmol DCPD/Al 100 200 360 Di-n-butyl ether/Al 2/1 2/1 2/1 Elapsed time until exotherm 40 sec. 55 sec. 144 sec.
Exotherm 150C 151C 145C

Examples 22-25 15 The effect of impurities on the catalyst system is illus-trated in Examples 22 through 25. In Example 22, a 0.007 ~l solution of ~C16/phenol in DCPD was prepaxed by mixing under nitrogen 150 ml of DCPD with 10.8 ml of a 0.1 M I~C16/phenol solution in toluene and 0.11 ml of benzonitrile. Then 3.0 ml of this solution was mixed under nitrogen with 3 ml of a DCPD
solution containing AlEt2Cl at a level DCPD to alkylaluminum of 150:1 and di-n-butyl ether at a level of ether to alkyl-aluminum of 1.5:1.
In Æxample 23, a 10 ml sample of the catalyst/monomer solution used in Example 22 was mixed with an impurity, 0.036 mmol of H20, added as a dispersion in DCPD. One and one-half hours later, 3 ml of this mixture was mixed under nitrogen with 3.01 of the activator/monomer solution described in Example 22. ~he reaction was repeated this time combining the activator/monomer solution with the catalyst/monomer solu-tion 18 hours after the ~2 had been added.
Example 24 was done in the same manner as Example 23 with the exception that 0.036 mmol of tert-butyl hydroperoxide was added to a second 10 ml sample of the catalyst solution rather than H20. The reactivity of the resultant mixture was checked 1 1/2 and 18 hours after the addition of the impurity. Exam-ple 25 was carried out in the same manner with the exception that 0.072 mmol of di-tert-butylperoxide was the impurity added initially to 10 rnl sample of the catalyst/monomer solu-tion. In every case a solid, insoluble polymer was formed.

La~le VII

Example 22 Example 23 Example 24 xample 25 DCPD 43 mmol 43 mmol 43 mmol 43 mmol WC16/Phenol 0.021 mmol 0.021 mmol 0.021 mmol 0.021 mmol 10 H20 ~ 0.01 mmol - -tert-butyl-hydroperoxide - - 0.01 mmol Di-tert-butyl-peroxide - - - 0.02 mmol 15 Et2AlC1 0.14 mmol 0.14 mmol 0.14 mmol 0.14 mmol Added Impurity/W 0 0.5/1 0.5/1 1/1 Induction Time after 1 1/2 hrs. 31 sec. 50 sec. 98 sec. 33 sec.
Exotherm after 1 1/2 hrs. 173C 171C 168C 171C
Induction time after 24 hrs. 36 sec. 98 sec. 266 sec. 73 sec.
Exotherm after 24 hrs. 170C 170C 155C 169C

Examples 26-33 Samples of polymerized DCPD were made by RIM processing using a standard RIM machine supplied by Accuratio Co. of Jeffersonville, Indiana. ~he following description illus-trates the standard procedure for molding samples. First the desired amount of DCPD was charged into two 2 gallon tanks.
The tanks are located on different sides of the RIM machine:
the tank on the A side is the one to which the activator was later added and the tank on the B side is the one to which the catalyst was later added. If desired, rubber and/or %

organic resins were added as a predissolved solution in DCPD.
Also solid fillers, if desired, were added.
The tanks were then closed off and inerted with nitrogen.
Sufficient Et2AlCl was transferred into the A tank to bring the alkylaluminum concentration to 0.048 M and sufficient di-n-butyl ether was added to achieve an ether to alkylaluminum ratio of 1.5:1. Next, sufficient WC16/phenol to bring the concentration of the catalyst in the B side to 0.007 M was added to the B tank. m~ he catalyst was added as a 0.1 M solu-tion in toluene. All transfers were done in a way to precludethe entrance of oxygen or moisture into the system. The materials were then thoroughly blended in their respective tanks.
The mixing of the A stream and the B stream was accom-plished using a standard impingement type RIM mixhead. Theratio of the activa-tor/monomer solution mixed with catalyst/
monomer solution was 1~ he impingement mixing was accom-plished by passing both the solutions through orifices 0.032"
in diameter at a flow rate approximately 80 ml/sec. This required pumping pressure of approxima-tely 1000 psi.
The resulting mixture flowed directly into a mold heated between 50C and 60C. The mold was made out of aluminum and was chrome plated. The mold had a flat cavity which formed a plaque sample 10" x 10" x 1/8" thick. A clamping force of 1.5 tons was used to keep the mold closed. mhe finished samples were removed at various times after mold filling ended.
In Example 26, the outlined molding procedure was fol-lowed where there was added 10 wt% added styrene-butadiene-styrene rubber (Kraton no. 1102 manufactured by Shell Chemical Co). The sample was removed from the molcl after 2 minutes.
In Example 27 a material of the same composition as Example 26 was produced. This time mold was opened 30 seconds after the combined streams were injected. The surface features of Exam-ple 27 were noticably better than those of ~xample 26. In Example 28, 10 wt% of a thermally polymerized dicyclopenta-diene resin was added in addition to both the catalyst/monomer and -the activator/monomer solutions in addition to the sty-rene-butadiene-styrene rubber.
Trade ~arl~

Various inorganic fillers were incorporated into the DCPD
polymer by adding equal amounts to both the catalyst/monomer and the activator/monomer solutions. In Example 29, samples were made containing 33 wt% 1/8" milled glass (P117B grade of Owens Corning Co.). These samples were made by initially slurrying the glass into both solutions the catalyst/monomer and the activator/monomer otherwise, these solutions were identical to those used in Example 28. In Example 30 a compo-sition consisting of 10 wt% wollastonite was made by adding the filler to a formulation identical to that described in Example 28. In Example 31 the same procedure was followed as in Example 30 except that a 33 wt% level of wollastonite was employed. In Example 32, 25 wt% wollastonite was added to formulation described in Example 27. In each case a solid, insoluble polymer is formed. Representative properties of Examples 26-32 are listed in Table VII.
Example 33 is a RIM processed poly(DCPD) made without any rubber additives.

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Claims

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:

1. A method of making a thermoset homopolymer comprising:
combining a plurality of reactant streams, one of which contains the activator of a metathesis-catalyst system, and a second which contains the catalyst of said metathesis-catalyst system, and at least one of which contains dicyclopentadiene to form a reaction mixture and then, immediately injecting the reaction mixture into a mold where polymerization occurs.

2. A method in accordance with claim 1 characterized in that the dicyclopentadiene is endo-dicyclopentadiene which has been purified by removing volatiles which distill below 100°C at about 90 ? 3 torr.

3. A method in accordance with claim 1 further characterized in that the catalyst is a tungsten containing compound.

4. A method in accordance with claim 1, 2 or 3 characterized in that the catalyst is a tungsten containing compound which is selected from the group consisting of tungsten hexachloride and tungsten oxy tetrachloride.

5. A method in accordance with claim 1, 2 or 3 characterized in that the catalyst is tungsten hexachloride.

6. A method in accordance with claim 1, 2 or 3 characterized in that the catalyst is mixed with dicyclopentadiene before the catalyst is mixed with the activator.

7. A method in accordance with claim 1, 2 or 3 characterized in that the catalyst is a tungsten containing compound which is incorporated into a reactant stream by dissolving the tungsten compound in a solvent, incorporating the solvent containing the catalyst in dicyclopentadiene and also incorporating in the dicyclopentadiene from about 1 to about 5 moles of a Lewis base or a chelating agent, per mole of tungsten compound, to prevent premature polymerization.

8. A method in accordance with claim 1, 2 or 3 characterized in that the activator is an alkylaluminum halide, where the alkyl group contains one to ten carbon atoms.

9. A method in accordance with claim 1, 2 or 3 characterized in that the activator is selected from the group consisting of diethyl aluminum chloride and ethyl aluminum dichloride.

10. A method in accordance with claim 1, 2 or 3 characterized in that the activator is diethyl aluminum chloride.

11. A method in accordance with claim 1, 2 or 3 characterized in that the activator is combined with a moderator.

12. A method in accordance with claim l, 2 or 3 characterized in that the activator is combined with a moderator which is selected from the group consisting of isopropyl ether, di-n-butyl ether, ethyl benzoate, phenyl ethyl acetate and diisopropyl ketone.

13. A method in accordance with claim 1, 2 or 3 characterized in that the activator is combined with a moderator which is selected from the group consisting of ethyl benzoate and di-n-butyl ether.

14. A method in accordance with claim 1, 2 or 3 characterized in that the activator is combined with a moderator in an activator to moderator ratio from about 1:1.5 to about 1:5.

15. A method in accordance with claim 1, 2 or 3 characterized in that the activator is mixed with dicyclopentadiene before the activator is mixed with the catalyst.

16. A method in accordance with claim 1, 2 or 3 characterized in that the reaction mixture has a dicyclopentadiene to catalyst ratio of about 1,000:1 to about 15,000:1.

17. A method in accordance with claim 1, 2 or 3 characterized in that the reaction mixture has a dicyclopentadiene to catalyst ratio of about 2,000:1.

18. A method in accordance with claim 1, 2 or 3 characterized in that the reaction mixture has a dicyclopentadiene to activator ratio of about 100:1 to about 2,000:1.

19. A method in accordance with claim 1, 2 or 3 characterized in that the reaction mixture has a dicyclopentadiene to activator ratio from about 200:1 to about 500:1.

20. A method in accordance with claim 1, 2 or 3 characterized in that an elastomer is added to at least one of the reactant streams in an amount sufficient to make the viscosity of the reaction mixture between about 300 and about 1000 cps.

21. A method in accordance with claim 1, 2 or 3 characterized in that a styrene-butadiene-styrene elastomer is added to at least one of the reactant streams in an amount sufficient to make the viscosity of the reaction mixture between about 300 and about 1000 cps.

22. A method in accordance with claim 1, 2 or 3 characterized in that up to about 2.0 wt % of a phenolic or amine antioxidant is incorporated in the reaction mixture.

23. A method in accordance with claim 1, 2 or 3 characterized in that the reactant streams are combined in the mixing head of a RIM machine and the combined mixture is injected into a mold maintained at a temperature of about 35 to about 100°C and a pressure of about 10 to about 50 psi.

24. A method in accordance with claim 1, 2 or 3 characterized in that the homopolymer is subjected to post-curing at about 175°C for about 15 minutes.

25. A catalyst part of a metathesis-catalyst system comprising a catalyst and a Lewis base or a chelant wherein the molar ratio of catalyst to Lewis base or chelant is about 1:5, which catalyst part is suitable for use with an activator part in the dicyclo-pentadiene and a moderator, wherein the activator is an alkyl-aluminum compound and the ratio of alkylaluminum to moderator is from about 1:1.5 to about 1:5 on a molar basis, to form the meta-thesis-catalyst system.

26. A catalyst part of a metathesis-catalyst system as claimed in claim 25 comprising a catalyst and a chelant wherein the molar ratio of catalyst to chelant is about 1:5, and said chelant is selected from the group comprising acetylacetone and alkyl aceto-acetates.

27. A catalyst part of a metathesis-catalyst system as claimed in claim 25 or 26 wherein the catalyst contains tungsten.

28. A catalyst part of a metathesis-catalyst system as claimed in claim 25 or 26 wherein the catalyst is a tungsten halide or tungsten oxyhalide.

29. A catalyst part of a metathesis-catalyst system as claimed in claim 25 or 26 wherein the catalyst is WCl6 or WOCl4.

30. An activator part of a metathesis-catalyst system in dicyclopentadiene and a moderator, wherein the activator is an alkylaluminum compound, the ratio of alkylaluminum to moderator is from about 1:1.5 to about 1:5 on a molar basis, and the activa-tor part is suitable for use with a catalyst part comprising a catalyst and a Lewis base or a chelant, wherein the molar ratio of catalyst to Lewis base or chelant is about 1:5, to form the metathesis-catalyst system.

31. An activator part of a metathesis-catalyst system as claimed in claim 30 wherein the activator is an alkylaluminum dihalide or dialkylaluminum halide wherein the alkyl group contains one to ten carbon atoms, and the moderator is selected from iso-propyl ether, di-n-butyl ether, ethyl benzoate, phenylethyl acetate and diisopropyl ketone.

32. An activator part of a metathesis-catalyst system as claimed in claim 30 or 31 wherein the activator is diethyl aluminum chloride and the moderator is ethyl benzoate or di-n-butyl ether.

33. A thermoset dicyclopentadiene polymer having a flexural modulus in the range of 150,000 to about 300,000 psi and a notched Izod impact strength of at least 1.5 ft. lb./in. notch and which also contains an elastomer.

34. A thermal dicyclopentadiene polymer as claimed in claim 33 wherein the elastomer is a natural rubber, butyl rubber, polyiso-prene, polybutadiene, polyisobutylene, ethylene-propylene copoly-mer, styrene-butadiene-styrene triblock rubber, styrene-isoprene-styrene triblock or an ethylene-propylene diene terpolymer.

35. A thermoset dicyclopentadiene polymer as claimed in claim 34 wherein the amount of elastomer does not exceed about 10% by weight.

36. A thermoset dicyclopentadiene polymer as claimed in claim 33, 34 or 35 in which there is incorporated from about 5% to about 75% of a filler.

37. A thermoset dicyclopentadiene polymer as claimed in claim 33, 34 or 35 in which there is incorporated from about 5% to about 75% of a filler selected from the group consisting of glass, wollastonite, mica, carbon black, talc and calcium carbonate.